Communications for Model. Seth Neumann

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Communications for Model

Railroads

Seth Neumann

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Agenda

• Design Considerations

• Modeling From the Prototype

• What Era are You Modeling?

• How to Put it Together

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Design Considerations

Era/Technology Jobs you want

to model

Prototype Space in your

Railroad room

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Communications for Operations

• Different eras had different dispatching

models based on available

communications

– TT&TO: Telegraph/Telephone:

– CTC: Telephone/Radio

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Communications Time Line

• 1845: Telegraph invented

• 1850: Telegraph used by Railroads

• 1851: Charles Minot uses Telegraph to send 1st _{Train Order on}

Erie RR

• 1869: Telephone invented

• 1920s: Telephone in widespread use for TT&TO dispatching • 1920s: Telephone in widespread use for TT&TO dispatching

• 1925: CTC appears, phone booths provided at ends of controlled sidings

• 1940s: Telegraph largely supplanted by Telephone • WWII: CTC becomes common on western mainlines

• 1960s: Radio becomes widespread, Train Orders copied over radio

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Your Prototype

• What did your prototype do in your era?

– Single track with passing sidings?

– Double track, rule 251?

– Style of dispatching:

• TT&TO • TT&TO • CTC/TCS • Radio

• TT&TO requires Train Order Offices,

preferably with Train Order signals

• CTC requires phones at each controlled

signal

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Modeling Jobs on The Railroad

Operations is modeling the work of the

railroad. Like everything else in model

railroading, jobs are selectively

compressed: we like to do the fun parts but

not the boring, tedious and dangerous

parts. In the transition era there were 10

clerks for every one person in train service.

We could not fit all of the clerks for one

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Jobs to Model:

• Dispatcher

• Train Crews

• Agent/Operators (for TT&TO)

– One for whole layout?

– One at each station?

– Where you can fit them in?

– Train crew becomes often magically

becomes agent at each TO office

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What communications are you

trying to model?

• Communications among DS and Operators? (TT&TO)

– Open speakers – a Radio Shack intercom is a quick and dirty

choice IF the DS and Agent/Operators are in quiet places, isolated from the railroad. You could also build something using phone hardware OR

– Telegraph (RR Morse or International Morse)

– Use phones with amplified speaker across the line, provide Push – Use phones with amplified speaker across the line, provide Push

to Talk and/or noise canceling microphone to control feedback

– Remember real crews rarely OSd themselves, so having crew OS is generally a “model railroad thought”

• Communications between DS and crews (CTC)

– Idea is to keep crews “isolated” (no radio chatter) – Need to go to a “station” or phone booth to talk

– “Call Lamps” on relay shacks set by DS on the CTC machine

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Your Layout: Givens and

‘Druthers

• How much space do you have?

– Do you have room for sound-isolated Agent’s stations? – Where to place telephones (by the station –TT&TO, at

controlled signals –CTC) – Aisle width

– Places to write

• How much chatter do you want in the layout • How much chatter do you want in the layout

room?

• Arrangements for displaying train order signals, (Semaphores, Searchlights, hooks below layout) • Do you want prototypical phone instruments or

would more comfortable and durable (and potentially less expensive) modern (but anachronistic) equivalents be better?

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How should it work? - 1

• DS Calls a train:

– DS sets Signal to “stop” at station in front of train

– DS sets call lamp switch at that station – DS presses code button

– DS presses code button

– lamp on “phone booth” lights & locks

– Crew picks up phone (having seen lighted phone booth on arrival at station)

– Crew announces “Hearst”

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How should it work? - 2

• Train Crew calls from Siding:

– Conductor goes off hook at phone and

announces [“Hearst”]

– DS hears speaker or DS phone

buzzes

– Or DS goes off hook – buzzer stops

(speaker muted, if present)

– DS answers

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How to Model under CTC

-Planning

• Assumes you have a CTC Board

• Determine where the DS will work. Is it a separate room?

• Determine where the phones will be. Do you have room for a phone at each end of each controlled room for a phone at each end of each controlled siding?

• Find a clean, well lighted place for the common

equipment. Be sure there is room to work, you’ll be spending some time here!

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How to Model it - Station

• There are many ways to do stations

• Here’s what Tommy Holt did: (note the Call Lamp on the phone)

• I recommend the stations • I recommend the stations

have PTT and/or noise canceling mics

• Enforce communications discipline! Don’t talk until the line is clear.

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Possible Station Solutions

Custom w/ PTT Most flexible, best performance

$100

Vintage swap meets, web

vendors

$50-250

554 Wall Set Whatever you can < $50

554 Wall Set Whatever you can

find, garage sales

< $50

WallMart Cheapie on modular plate

Buy a few spares, anachronistic.

Some control

circuits won’t work

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Stations

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“Space Saver”

• W.E 211 type “space saver”

• Doesn’t take much space in aisle • Needs external speech network

and ringer/buzzer*

• Appropriate for 20’s thru 80’s • Appropriate for 20’s thru 80’s • Originally had E or F type

handset – consider replacing with G type handset (correct for 50s and 80s)

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302 Set

• 302 type desk set

• Has internal speech network

• Appropriate for 30s through early 50s • Equipped with F type handset

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500/554 Set

• 500 type desk set

• Designed by Henry Dreyfus of NYC fame

• Improved internal speech network

• Appropriate for 50s through early 80s

early 80s

• Equipped with G type handset

• Has extra hook switch contacts

• Phoneco >= $99, often available cheap at garage sales and swap meets

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Roll your own

• Electrically a 500 set

– G type handset – 425e network

– Cradle and hookswitch

• Can be panel or Fascia

mounted

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How to Model it - Dispatcher

• If there is a separate, sound-isolated room for the CTC machine, I recommend using the microphone

/speaker/footswitch arrangement. Depending on your precise era, you may want to match the photos of your dispatcher’s office at that date.

• If not, it’s probably best to use a noise canceling • If not, it’s probably best to use a noise canceling

headset. These are available from many vendors and can work with virtually any phone. Your regular

dispatchers may use one at work.

• In any case the DS should be able to work with both hands free.

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Possible Dispatcher Solutions

Scissor Mount with Headset (listen on headset) Antique telephone suppliers < $500 “PA” type microphone with Commercial sources $50-250 microphone with speaker

Modern Phone with headset (listen on headset)

HelloDirect, etc < $250

Modern Phone with buzzer, relay control

Whatever you can find, garage sales

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Dispatcher Arrangement

TIP

RING

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Dispatcher Foot Switch

• Use a period phone style switch

• Use a commercial switch

• Use the switch from your resistance

soldering rig with an AC relay

• Make one

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Common Equipment

• Power Supply – 24VDC regulated, a

(250mA regulated) wall wart will work

• A “Battery Feed” coil. These are balanced

chokes found in classic telephone circuits

• Amplifiers for DS (mic/spkr) or a pair of

relays and a buzzer.

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What is “Battery Feed?”

• Power

• DC v. AC

• What is “impedance?” (Z)

– Think of it as AC resistance

– A component (usually a choke coil) can have

low DC R but high AC Z!

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Battery feed alternatives

• Telco style Intercom

• Battery feed relay (24 or 48V)

• Audio Freq chokes

• Retard coil (2A, 31A, 401A KTUs,)

• PBX is not recommended

The goal is to have a relatively low DC Resistance (to power the phone) while keeping the impedance (AC resistance) at voice frequency as high as possible so we don’t lose speech energy through the power supply (so we can hear).

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Simple Phone System

TIP

RCVR

XMTR

Handset Network Hook Switch Battery Feed Inductor GN R C RR RING 1 3 5 4 Power Supply + -18-24 VDC B C “A” 3 4

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-Noise/Adequate Volume

• Use high impedance battery feed if possible

• Busy indicator to warn of conversation in

progress (user discipline)

• Push-to-talk (PTT) and/or noise canceling

handsets

• DO NOT use amplified handsets: they amplify

the noise in the room, too!

• Large systems (more than 4 stations off hook at

once) may require a distribution amp

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Large System Issues

• Have more stations (5 – 20)

• More phones off hook as crews tend to

call in every time they see a red signal

• More phones means more ambient noise

and less volume – combining loss

• Traditional phones don’t work well with >

4 off hook – Communications Discipline!

• Systems with active combiners and

amplification work better with large

numbers of phones off hook

• Ken Thompson, Bruce Chubb made

systems like this

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Other

• Use Cat 5 ($120/kft), has 4 pair, or CAT 3

(if you can find it) for station wiring

• Use twisted pair, helps reject noise

(leakage from DCC)

• Use terminal strips or telephone style 66

blocks for connections

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Radio

• Use FRS radios (some layouts still have 5

channel)

• All units should use headsets to keep

noise down, except isolated dispatcher

• Can modify a handheld for PTT service

• Do not use VOX

• Don’t need to use subchannel if there isn’t

much interference – quicker response

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Phone Resources

• Phoneco 608-582-4124

– www.phonecoinc.com

• Antique phone collectors site

– atcaonline.com/diagrams.html

• Graybar (San Jose) 408 441-9009

– www.graybar.com

• Telephone Components

– http://www.telephonecomponents.com • Hello Direct – http://www.hellodirect.com/